1. Field of the invention
The present invention concerns a protective switch device of the circuit-breaker or contactor/circuit-breaker type comprising at least one double-contact switch pole provided with a mobile contact bridge, a mobile support accommodating said contact bridge(s) and a contact pressure spring associated with each bridge.
In a device of this kind, commanded displacement of the support is adapted to cause displacement of the bridges; the bridges may be displaced relative to the support to enable the application of pressure to the contacts by springs. In the event of an electrical fault affecting at least one pole a magnetic and/or thermal tripping mechanism is adapted to operate via a control part to cause omnipolar opening of the contacts, for example by means of slide members movably mounted in the support; if the device is a contactor/circuit-breaker, an electrically or manually generated opening or closing command is adapted to be exerted via another control part to cause omnipolar opening of the contacts, for example by means of the aforementioned slide members or by means of a cage surrounding the support.
2. Description of the prior art
A device of this kind is disclosed in the patents FR - 2 634 590 and EP - 270 158. It has the disadvantage that, when opening is commanded by a solenoid, the latter has to overcome the force of the contact pressure springs because the active contact part is applied directly to the bridges. Also, the contact bridge operating systems prevent the overall dimensions of the device from being reduced as much as would be desirable. If the fixed contacts of the same pole are moved closer together there is insufficient electrical insulation, especially if the pole is opened electrodynamically.
An object of the invention is to achieve excellent electrical insulation between the two pairs of contacts of each pole of a circuit-breaker when the contacts are opened, especially when they are opened by electrodynamic repulsion of the contacts.
Another object of the invention is to reduce the overall dimensions of the support for the contact bridges of a protective switch device and to enable the designer of the device to move the fixed contacts of the same pole closer together to reduce the overall dimensions of the device and the mass of the mobile bridge.
A final object of the invention is to reduce the operating forces required in a contactor/circuit-breaker device of the type described.